I just dont see a market for these anymore. Sure, I would probably buy one, for the right price, but I'd buy anything for the right price...
There are just so many other options out there. Single shot shotguns are still very common, so that eliminates that market. Bolt action rifles are so cheap, that pretty much elimiates that market. The 45-70 Marlins are reasonably cheap, and thats certainly the direction I would look if I wanted a 45-70, because it would be my bear gun, and a single shot is not a good bear gun IMO.
I dunno, there is something ###y about a single shot, but if I was actually going out hunting I would generally prefer a repeater of some sort, so it would probably end up as a range/plinking toy unless it was in a caliber that I didn't have something comparable to (like if it was a 22-250, and I didn't have anything smaller than my 270)